[Bug 1950959] [NEW] [SRU] Missing dependency in libqt5gstreamer-dev

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You have been subscribed to a public bug by Sudip Mukherjee (sudipmuk):

[ Impact ]

The package libqt5gstreamer-dev is mostly unusable for users whose development environment uses pkg-config to find dependencies.
If we use pkg-config to find the CFLAGS that are needed to link with libQt5GStreamer-1.0.so then that will fail.

An example command:

# pkg-config --cflags Qt5GStreamer-1.0
Package gobject-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `gobject-2.0.pc'
to the PKG_CONFIG_PATH environment variable
Package 'gobject-2.0', required by 'Qt5GLib-2.0', not found

[ Test Plan ]

 * Execute the command "pkg-config --cflags Qt5GStreamer-1.0" and cofirm
that pkg-config can find the CFLAGS needed to link with
libQt5GStreamer-1.0.so

[ Where problems could occur ]

 * The dependency fix alone should not cause any problem as its not
changing any part of the code. But another fix from Debian had to be
added, as without that fix the package is failing to build in Jammy.
And, this patch is removing a volatile qualifier from a variable. But
this patch is in Debian since Sept, 2022 without any report of
regression so I will assume there is little chance of regression on
adding it here in Jammy.

[ Other Info ]

 * the package mentioned in the bug is wrong, it affects qt-gstreamer source.
 
 * as mentioned above an extra Debian patch is needed. Without that patch the build fails in Jammy with the error:

/<<PKGBUILDDIR>>/elements/gstqtvideosink/gstqwidgetvideosink.cpp: In static member function ‘static GType GstQWidgetVideoSink::get_type()’:
/usr/include/glib-2.0/glib/gatomic.h:113:19: error: argument 2 of ‘__atomic_load’ must not be a pointer to a ‘volatile’ type
  113 |     __atomic_load (gapg_temp_atomic, &gapg_temp_newval, __ATOMIC_SEQ_CST); \
      |     ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/glib-2.0/glib/gthread.h:260:7: note: in expansion of macro ‘g_atomic_pointer_get’
  260 |     (!g_atomic_pointer_get (location) &&                             \
      |       ^~~~~~~~~~~~~~~~~~~~
/<<PKGBUILDDIR>>/elements/gstqtvideosink/gstqtvideosinkplugin.h:31:13: note: in expansion of macro ‘g_once_init_enter’
   31 |         if (g_once_init_enter(&gonce_data)) { \
      |             ^~~~~~~~~~~~~~~~~
/<<PKGBUILDDIR>>/elements/gstqtvideosink/gstqtvideosinkplugin.h:56:5: note: in expansion of macro ‘DEFINE_TYPE_FULL’
   56 |     DEFINE_TYPE_FULL(cpp_type, #cpp_type "_qt5", parent_type, Q_UNUSED)
      |     ^~~~~~~~~~~~~~~~
/<<PKGBUILDDIR>>/elements/gstqtvideosink/gstqwidgetvideosink.cpp:22:1: note: in expansion of macro ‘DEFINE_TYPE’
   22 | DEFINE_TYPE(GstQWidgetVideoSink, GST_TYPE_QT_VIDEO_SINK_BASE)
      | ^~~~~~~~~~~
make[4]: *** [elements/gstqtvideosink/CMakeFiles/gstqt5videosink.dir/build.make:227: elements/gstqtvideosink/CMakeFiles/gstqt5videosink.dir/gstqwidgetvideosink.cpp.o] Error 1


* The problem has been fixed in Debian with qt-gstreamer_1.2.0-5.2, so Lunar, Mantic and Noble are not affected. Only Jammy and Focal are affected.

[ Original Bug Description ]

After installing libqt5gstreamer-dev, the following command fails:

pkg-config --exists Qt5GStreamer-1.0 || echo "Failed"
Failed

more info:
pkg-config --cflags Qt5GStreamer-1.0
Package gstreamer-1.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `gstreamer-1.0.pc'
to the PKG_CONFIG_PATH environment variable
Package 'gstreamer-1.0', required by 'Qt5GStreamer-1.0', not found

After installing libgstreamer-plugins-base1.0-dev (also brings the
missing libgstreamer1.0-dev), it works.

* Ubuntu 20.04.3 LTS
* libqt5gstreamer-dev (1.2.0-5)
* amd64

** Affects: qtcreator (Ubuntu)
     Importance: Undecided
         Status: Fix Released

** Affects: qtcreator (Ubuntu Focal)
     Importance: Undecided
     Assignee: Sudip Mukherjee (sudipmuk)
         Status: In Progress

** Affects: qtcreator (Ubuntu Jammy)
     Importance: Undecided
         Status: Confirmed

** Affects: qt-gstreamer (Debian)
     Importance: Unknown
         Status: Fix Released


** Tags: focal jammy unmetdeps
-- 
[SRU] Missing dependency in libqt5gstreamer-dev
https://bugs.launchpad.net/bugs/1950959
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